New York's Daily News screamed "Goldman Sucks", while the New York Post, its tabloid rival, called Smith's open letter of resignation a "Front foot punch."

The letter, published in The New York Times on Wednesday, did not pull any punches as it accused Goldman chief executive Lloyd Blankfein of chucking the moral compass overboard in pursuit of profit. (An accusation Blankfein denied).

Without adding up the column inches, internet page views and tweets, it's impossible to get any measure of whether the Smith's spectacular departure has prompted greater waves in New York, where Goldman is headquartered, or London, where he worked. Either way, it's the first time how Wall Street works – or is alleged to work – has really made the national news in the US since the Occupy Wall Street movement emerged last autumn.

Almost four months after their first television debate, the battle among Republican candidates to take on President Barack Obama is still running. And none of the candidates – with the exception of Ron Paul – have shown any real appetite to talk about Wall Street, examine the causes of the financial crisis or outline a vision for how to avoid the next one. Whatever you think of Smith's complaints, they were never going to be amplified by the Republican race.

That's not to say Republican candidates haven't picked their own targets from the US business world to chew on and spit out. It's just that their ammunition has so far been fired elsewhere. Instead of well-heeled bankers, it's largely been turned on an electric car built by General Motors.

GM's Chevy Volt has been described by Mitt Romney as "an idea whose time has not come", while Newt Gingrich lambasted the car because you could not fit it with a gun rack. There are four reasons why the Volt has crashed into the Republican race.

Concern among US drivers over the safety of the technology behind electric cars was fanned late last year by news that a number of them had suffered from exploding batteries. Helpfully for Republicans, Obama has gone out of his way to associate himself with a car now branded by some as an "exploding Obamamobile". Speaking to the United Auto Workers Union last month, Obama said that "five years from now when I'm not president anymore, I'll buy one and drive it myself".

Thirdly, the Volt has, so far at least, been a failure. From Monday, GM is suspending production of the car for five weeks because it has too many of the models still to shift. The car-maker fell short of its goal of selling 10,000 last year, and most analysts believe its goal of selling 45,000 in 2012 is too ambitious.

There's no doubt the Volt's unwanted appearance in the Republican race has caused consternation in Detroit. Dan Akerson, GM's chief executive, told Congress in January that "although we loaded the Volt with state-of-the-art safety features, we did not engineer the Volt to be a political punching bag". It's not clear whether the political heat has hurt sales, but that's hard to tell when electric cars and plug-ins account for just 0.1pc of all car sales in the US.

Supporters of electric cars believe that a sustained rise in oil prices will ultimately convert more American drivers to a technology most are still unfamiliar with. And this brings us to the fourth, and most interesting, reason the Volt has taken centre stage as a political punch bag.

For Obama's opponents, the Volt is the perfect symbol of his failure to deliver a coherent energy policy. The charge sheet is that the technology is unreliable, the cars require government subsidies and, retailing at more than $40,000, they are out of reach of most consumers at a time when many Americans are grappling with higher petrol prices.

It's no surprise that the last month has seen Republican candidates increase their focus on gas prices, energy policy and cars. With unemployment falling – albeit not quickly – Republicans need a sharper weapon with which to attack the White House. The 15pc increase in petrol prices this year provides it. Tensions over Iran's nuclear programme showing little sign of easing, so it's hard to see the price people pay at the pump falling sharply.

All of which suggests that electric cars like the Volt are more likely to headline in the political debate over the next few months than banks like Goldman.